Machines for forming stator windings are known in which a needle, driven with rectilinear reciprocating motion combined with reciprocating rotary motion about its axis, carries at least one copper wire unwinding from a reel in order to deposit it in the stator armature slot. The needle comprises one point if a single winding is to be made, or comprises two opposing points if both windings are to be made simultaneously. In all cases, the needle always has its axis of advancement and rotation coinciding with the stator axis in order to enable it to slide in the open spaces between the slots within the stator during its to and fro movement and to lie equidistant from all the armature slots on which its points are to wind the copper wire.
In the case of a stator with two opposing windings, winding forms, also known as shoes, are applied to the ends of the respective slots, and are shaped in such a manner as to accompany or guide the copper wire of the needle into the slot, when the needle rotates external to the stator. These shoes have a basic and specific purpose in that, as stated, the needle is coaxial to the stator axis and thus its point cannot pass beyond the winding retention tooth during its rotation which takes place beyond the inner diameter of the stator, so that if the shoe is not used, the copper wire is unable to wind onto the slot beyond the retention tooth. If the retention tooth does not exist, only a few turns could be deposited, and these would represent only a small percentage of those required.
In addition to the need to construct these shoes accurately, they must also be properly sized for each stator to be constructed, even though they represent an element which forms no part of the final product. In this respect, the shoes are removed by two devices when the winding has been formed. Moreover, four tensioning devices have to be set up to hold the shoes rigidly against the stator during the forming stage, and to enable them to be rapidly released from it when the forming is complete.